JT1 I am very surprised that you were able to ride at Mamoth Bar with no spark arrestor. They are really tight there because of all the issues that the envoirmentalist are bringing up about the river. I was not allowed to ride there because my reg was not properly displayed (my bike was registered but I forgot to put my new sticker on). Two of my friends were not allowed to enter because of the spark arrestor. They are very strict at Mamoth Bar to say the least. I don't think that Stonyford is and OHV park like Hollister or Carnigy, it is like public land similar to Pie Pie or Crystal Springs Recreation area. I know that the maps for these places are the same/different in this relation.